Trying to change colours on the the same plot, but getting error message 'There is no b property on the Line class'

I am trying to create a plot which has all of the values negative values below 0 in red, and those positive, above 0 in blue.

However when I try to do this using 'b' for blue and 'r' for red, I am met with the message 'There is no b property on the Line class'

Unsure of where I'm going wrong if someone could please assist

               figure((iSubject-2)*100 + (iTest-4)*10 + (iGroup-2))
                    subplot(511)
                    plot(acc(:,1))
                    title('lower back')
                    positiveIndexes = 2 >= 0;
                    negativeIndexes = 2 <= 0;
                    hold on 
                    plot(acc(:,1),(positiveIndexes),'b',1)
                    plot(acc(:,1),(negativeIndexes),'r',1)

Answer 1

[ME]

The issue with your plotting command is that matlab is interpreting the 'b',1 part as a pair of commands (i.e. ste the property named b equal to 1). At present the 1 won't be doing anything - what was the purpose of the 1?

If you get rid of the ,1 at the end of your plotting command then it will plot in the right colours.

Answer 2

[Cameron Kirk]

Thanks for that, I was trying to mirror a code from someone else, so that one wasn't needed!